Walking along the shoreline of a lake and finding a shell or rock that's visually interesting is not an unusual occurrence. It's not even unusual to find one that's from a different time period, especially on the shores of the Great Lakes. What is unusual, however, is finding a rock that glows under ultraviolet light - and not just in a dim and unimpressive way.
Ceratin rocks have special mineral compositions that allow them to react differently under various light sources. While hunting for unique finds along the shores of Lake Superior during the day might yield nothing but ordinary stones, hunting at night, with a UV source, sheds a different light on these rocky shores.
Science Behind The Fluorescent Great Lakes Rocks
Dubbed 'Yooperlites' by Erik Rintamaki, who has a lifelong experience of rock-hunting and specializes in syenite rocks, these are unique stones to find along Lake Superior's shores. His collection, alone, would make anyone eager to run out to the beach and start shining a UV light around just to find one of their own. While the Great Lakes have many qualities that make them one of the most unique sets of waterways in the country, their glowing rocks are perhaps one of the most mystifying. On the outside, these rocks don't look like anything of substance; once exposed to UV light, they come alive with bold oranges, neon greens, electric blues, and brazen red hues to create some of the most intriguing rocks you're likely to ever see in your life.
What gives these rocks their signature glow is the addition of sodalite - but that's not all. While Lake Superior's rocks are rich in this mineral, there are a total of 500 minerals that give off the same UV light glow. It's just not often that anyone thinks to check them under a light other than one that comes from the sun. In short, the atoms within these mineral compounds become excited under a UV light source which leads to their unique, lit-from-within appearance.
How To Find These Glowing Rocks
Believe it or not, it's not overly challenging to find rocks that glow under a UV light such as those that exist along the shores of the Great Lakes. However, rock-hunters will need a few things to get started:
- A strong UV light source, preferably in the form of a flashlight
- Good shoes for walking on rocky shores
- A bag or container to hold rocks in
It goes without saying that the best - and, really, the only - time to go searching for these rocks is after dark. According to Rintamaki, the best way to sweep the shoreline is to stand in one place, sweep over it slowly with the flashlight, and then take another short, small step forward - then repeat the process. According to Atlas Obscura, Rintamaki says that finding the rocks sometimes takes no more than a 200-foot walk down the shoreline before finding something truly special. In fact, the rocks are all over the place; specifically, anywhere one would find a glacial till which is what's believed to have created these unique compounds.
Tours With Rintamaki
Those interested in finding these unique rocks along the shores of Lake Superior, specifically, can book tours with Rintamaki through his Yooperlites website. This is a great way to find glowing rocks with an experienced guide who not only knows where to look but knows exactly how to search, as well. Not to mention, exploring the shores of Lake Superior just after dusk is quite an experience in itself.
- Cost: $150/person
- Guided Tour Dates: Tours are available Monday-Sunday, but specific dates vary from week to week
- Tour Times: July - 8:30 PM, August - 8:15 PM, September - 7:45 PM, October - 7:30 PM
- Tour participants are also given a Convoy C8 Yooperlite Hunter Package (value of more than $100)
What To Be Wary Of While Hunting
When one is so focused on the task at hand, it can sometimes be easy to forget how to remain in the moment while also being cautious of one's surroundings. In that same interview with Atlas Obscura, Rintamaki also detailed his process when searching a new area, giving the recommendation of scouting out the location on Google Maps before heading in aimlessly.
Some tips for first-timers:
- Bring a buddy. The first time anyone is searching for something in the dark, it's smart to use the buddy system, especially in a new place.
- Remember to pack a regular flashlight, as well. UV light is great for hunting glowing rocks but doesn't do much to aid in lighting the way back.
- Don't venture in too far. And if you do, be sure to mark the trail with something such as glowsticks so that you can find your way back.
- Scout out the area during the day, first. Know what you're walking into and familiarize yourself with the terrain.